The multiverse is a result of following Schroendingers wave equations to it’s end. It inventor was Everett. Sean Carroll is now it’s main champion. Look it up. It also requires faith for it seems impossible to test.
My brother says Hugh was the smartest person he ever worked with (principals of a think tank).
The multiverse is a cop-out to avoid the teleological / philosophical implications the Universe actually having a beginning; as well as an escape from the anthropic principle.
I lost the article, but IIRC Larry Krausse (who, yes, was associated with the Epstein who didn’t kill himself) admitted as much about it in a newspaper interview years ago.